17374-71-9Relevant academic research and scientific papers
Electrostatic Catalysis by Ionic Aggregates. 6. Modulation of Proton-Transfer Equilibria by Lithium Perchlorate-Diethyl Ether Clusters
Pocker, Y.,Ciula, James C.
, p. 2904 - 2909 (1988)
This study shows that the proton-transfer reaction of tropolone (2-hydroxy-2,4,6,-cycloheptatrien-1-one) with amine bases in diethyl ether is subject to substantial changes in the apparent equilibrium constant with changes in the concentration of lithium
Reactions of dihalobenzene radical cations with ammonia in the gas phase. Reactivity pattern for nucleophilic aromatic substitution
Th?lmann, Detlef,Grützmacher, Hans-Friedrich
, p. 3281 - 3287 (2007/10/02)
The reactions of homo- and heterodisubstituted dihalobenzene radical cations with NH3 were investigated by FT-ICR spectrometry. A halogen atom X (X = Cl, Br, I) is substituted in a gas-phase nucleophilic ipso substitution, yielding haloanilinium ions. The reaction efficiency, i.e., the percentage of reactive ion-molecule collisions, ranges from 3 proceeds by a multistep reaction mechanism with a double-well potential energy surface. The rate-determining step is the addition of NH3 to the aromatic radical cation in the collision complex. The structural parameters influencing this reaction step can be analyzed by the reactivity model of polar reactions of Shaik and Pross. From this the most important feature of the substitution reaction of mono- and dihalobenzene radical cations with NH3 is the different charge localization in reactants and products. This results in a strong influence of the difference of the ionization energies of the halogenated benzene and NH3 and of the dipole moment of the halogenated benzene, i.e., the precursor of the ionic reactant, on the activation energy of the addition step.
